1. Field of the Invention
The present invention relates to a paint cup and, more particularly, to a paint cup for a spray gun which features no vent jammed by paint.
2. Description of the Related Art
U.S. Patent Publication No. 2010/0301049 A1 discloses a lid for a closeable mixing cup for a paint gun. The lid is provided with a ventilation opening. The ventilation opening is embodied as a labyrinth seal with three cylinders inserted into each other and allowing air to flow. In a preferred embodiment shown, the three cylinders includes an exterior cylinder embodied in one piece with the lid and extending into an interior space of the mixing cup, an interior cylinder provided inside the exterior cylinder and embodied in one piece with the lid, and a snapping part arranged at the bottom end of the exterior and interior cylinders and including a cylindrical part which projects upwards and falls short of an axial length of the exterior and interior cylinders. The interior cylinder is embodied open towards the top. The cylinder part is inserted with little play into a space between the exterior and interior cylinders and closes the interior of the interior cylinder towards the bottom, but not sealing it completely. Air could enter via the interior cylinder at the bottom end of the interior cylinder into the space between the exterior and interior cylinders, and air can pass the cylinder part and exit again downwards, forming an air bridge from the exterior of the mixing cup and/or lid to the interior space of the mixing cup. This air bridge is easily possible, if the individual dimensions are sized sufficiently small, so that paint located in the interior space of the mixing cup cannot penetrate this path to the outside. However, the gaps between the cylinder part and the exterior and interior cylinders can not be appropriately controlled, so that paint dripping through the labyrinth seal can still occur during shaking of the mixing cup by a user. Furthermore, viscous liquid paint residuals remaining between the exterior cylinder and cylinder part will flow into the bottoms of the exterior cylinder and cylinder part and further flow into the bottoms of the exterior and interior cylinders and adhere to surfaces of all cylinders when the paint cup is reversed again in the case of the paint gun unused or addition of paint. Accordingly, the gaps between the cylinders will be narrowed with time, resulting in an adverse impact on the function of the ventilation opening and even making the paint gun unavailable.